Objectives: This retrospective, multicentre, observational study aimed to assess the mean annual doses and associated costs of three anti-tumour necrosis factor agents in daily clinical practice in rheumatoid arthritis patients, correlating these costs with disease activity.
Methods: Adult rheumatoid arthritis patients were treated and followed at the Rheumatology departments of two Spanish hospitals for at least 6 months, with adalimumab, etanercept or infliximab over a 4-year period. ANOVA and multivariate statistical analyses of dosing patterns, disease activity and annualised costs were carried out.
Results: A total of 198 patients, comprising 215 cases, met the inclusion criteria (73 on adalimumab, 81 etanercept and 61 infliximab). Compared to recommended doses, mean doses of adalimumab and etanercept decreased by 7% and 19%, respectively, while the mean dose of infliximab increased by 36%. There were no statistical differences between treatments in terms of clinical effectiveness. The hazard of dose escalation was significantly higher for either adalimumab (4.4-fold) or infliximab (11.8-fold) compared to etanercept (p<0.05). Clinical control was achieved and maintained in more than half of the patients treated with reduced doses of etanercept. Associated mean patient-year costs were significantly higher in adalimumab patients (€11.962.58) (etanercept €9.594.73; infliximab €10.094.53; [p<0.05]).
Conclusions: In rheumatoid arthritis patients, it is possible to reduce doses and associated costs of biological therapies while controlling disease activity. Mean doses used in our clinical practice were significantly lower with etanercept than with the anti-TNF monoclonal antibodies, adalimumab and infliximab. Dose differences impact directly on associated patient-year costs, and thus on treatment efficiency.